Airfoil having forward flowing serpentine flow

Abstract

Airfoils including an airfoil body having leading and trailing edges and root and tip regions, wherein an aftward direction is from the leading edge toward the trailing edge and a radially outward direction is from the root region to the tip region, a forward-flowing serpentine flow path within the airfoil body defined by a first serpentine cavity, a second serpentine cavity, and a third serpentine cavity, wherein the first serpentine cavity is aftward of the second serpentine cavity, and the second serpentine cavity is aftward of the third serpentine cavity, a flag tip cavity extending aftward from proximate the leading edge to the trailing edge along the tip region, and a hybrid trailing edge cavity, wherein the first serpentine cavity is part of the hybrid trailing edge cavity and cooling air is supplied into the forward-flowing serpentine flow path from a hybrid trailing edge feed cavity inlet.

What is claimed is: 
     
       1. An airfoil for a gas turbine engine, the airfoil comprising:
 an airfoil body having a leading edge and a trailing edge, a root region and a tip region, wherein an aftward direction is from the leading edge toward the trailing edge and a radially outward direction is from the root region to the tip region; 
 a forward-flowing serpentine flow path formed within the airfoil body, the forward-flowing serpentine flow path defined by a first serpentine cavity, a second serpentine cavity, and a third serpentine cavity, wherein the first serpentine cavity is aftward of the second serpentine cavity, and the second serpentine cavity is aftward of the third serpentine cavity; 
 a flag tip cavity extending aftward from proximate the leading edge to the trailing edge along the tip region of the airfoil body; 
 a hybrid trailing edge cavity, wherein the first serpentine cavity is part of the hybrid trailing edge cavity; and 
 at least two shielding cavities located on a pressure side of the airfoil body between a portion of the forward-flowing serpentine flow path and an external surface along the pressure side of the airfoil body, wherein the at least two shielding cavities are fluidly separate from the forward-flowing serpentine flow path and fluidly separate from each other within the airfoil body, 
 wherein a cooling air flow is supplied into the forward-flowing serpentine flow path from a hybrid trailing edge feed cavity inlet at the hybrid trailing edge cavity, and the cooling air flow passes through the first serpentine cavity, the second serpentine cavity, the third serpentine cavity, into and through the flag tip cavity, and exits through the trailing edge of the airfoil body, and 
 wherein a portion of the cooling air flow exits the hybrid trailing edge cavity at the trailing edge of the airfoil body. 
 
     
     
       2. The airfoil of  claim 1 , wherein the hybrid trailing edge cavity comprises one or more heat transfer augmentation features. 
     
     
       3. The airfoil of  claim 1 , wherein the tip flag cavity comprises one or more heat transfer augmentation features. 
     
     
       4. The airfoil of  claim 1 , wherein the at least two shielding cavities comprise a first shielding cavity and a second shielding cavity. 
     
     
       5. The airfoil of  claim 1 , wherein each shielding cavity extends radially through the airfoil body from the root region to the tip region. 
     
     
       6. The airfoil of  claim 1 , further comprising a radially extending partitioning rib extending radially and separating the hybrid trailing edge cavity from the second serpentine cavity, wherein the hybrid trailing edge cavity is fluidly connected to the second serpentine cavity at a radially outward end of the radially extending partitioning rib. 
     
     
       7. The airfoil of  claim 6 , further comprising a resupply connection fluidly connecting the hybrid trailing edge cavity to the second serpentine cavity at a radially inward end of the radially extending partitioning rib. 
     
     
       8. The airfoil of  claim 1 , further comprising a platform wherein the root region of the airfoil body is integral with the platform. 
     
     
       9. The airfoil of  claim 8 , wherein the hybrid trailing edge feed cavity inlet supplies serpentine cooling air through the platform and into the airfoil body. 
     
     
       10. A gas turbine engine comprising:
 a turbine section comprising a plurality of airfoils, wherein at least one airfoil comprises: 
 an airfoil body having a leading edge and a trailing edge, a root region and a tip region, wherein an aftward direction is from the leading edge toward the trailing edge and a radially outward direction is from the root region to the tip region; 
 a forward-flowing serpentine flow path formed within the airfoil body, the forward-flowing serpentine flow path defined by a first serpentine cavity, a second serpentine cavity, and a third serpentine cavity, wherein the first serpentine cavity is aftward of the second serpentine cavity, and the second serpentine cavity is aftward of the third serpentine cavity; 
 a flag tip cavity extending aftward from proximate the leading edge to the trailing edge along the tip region of the airfoil body; 
 a hybrid trailing edge cavity, wherein the first serpentine cavity is part of the hybrid trailing edge cavity; and 
 at least two shielding cavities located on a pressure side of the airfoil body between a portion of the forward-flowing serpentine flow path and an external surface along the pressure side of the airfoil body, wherein the at least two shielding cavities are fluidly separate from the forward-flowing serpentine flow path and fluidly separate from each other within the airfoil body, 
 wherein a cooling air flow is supplied into the forward-flowing serpentine flow path from a hybrid trailing edge feed cavity inlet at the hybrid trailing edge cavity, and the cooling air flow passes through the first serpentine cavity, the second serpentine cavity, the third serpentine cavity, into and through the flag tip cavity, and exits through the trailing edge of the airfoil body, and 
 wherein a portion of the cooling air flow exits the hybrid trailing edge cavity at the trailing edge of the airfoil body. 
 
     
     
       11. The gas turbine engine of  claim 10 , wherein at least one of the hybrid trailing edge cavity and the tip flag cavity includes one or more heat transfer augmentation features. 
     
     
       12. The gas turbine engine of  claim 10 , wherein the at least two shielding cavities comprise a first shielding cavity and a second shielding. 
     
     
       13. The gas turbine engine of  claim 10 , wherein each shielding cavity extends radially through the airfoil body from the root region to the tip region. 
     
     
       14. The gas turbine engine of  claim 10 , the airfoil body further comprising a radially extending partitioning rib extending radially and separating the hybrid trailing edge cavity from the second serpentine cavity, wherein the hybrid trailing edge cavity is fluidly connected to the second serpentine cavity at a radially outward end of the radially extending partitioning rib. 
     
     
       15. The gas turbine engine of  claim 14 , the airfoil body further comprising a resupply connection fluidly connecting the hybrid trailing edge cavity to the second serpentine cavity at a radially inward end of the radially extending partitioning rib. 
     
     
       16. The gas turbine engine of  claim 10 , further comprising a platform wherein the root region of the airfoil body is integral with the platform.